Large earthquake strikes off Alaska coast, prompting tsunami warnings

A 7.5-magnitude earthquake struck off the coast of Alaska near midnight on Friday, the U.S. Geological Survey said, prompting tsunami warnings and advisories down the coast of Alaska and Canada's British Columbia.

The Alaska Tsunami Warning Center said the waves were too small to pose a threat, reaching just six inches above normal sea level in places such as Sitka and Port Alexander.

"Initially, in the first 15 to 20 minutes, there might have been a bit of panic," Sitka Police Chief Sheldon Schmitt told The Associated Press. But he said things calmed down as the town waited for the all clear and the tsunami warning was canceled by 2 a.m., according to the Daily Sitka Sentinel.

Residents of Sitka gathered at the high school early Saturday, bundled up with pillows in tow, waiting for more information.

The quake struck in the Pacific Ocean about 60 miles southwest of Port Alexander, Alaska, at a depth of about 6 miles at 11:58 p.m. local time (3:58 a.m. ET), the USGS said.

Initially, the USGS reported that the temblor had a magnitude of 7.7, but it later downgraded the quake's strength to 7.5.

"A tsunami was generated by this event but does not pose a threat to these areas," NOAA said in a statement. "Some areas may see small sea level changes. The decision to re-occupy hazard zones must be made by local authorities."

The NOAA also issued tsunami advisories from the Washington state-British Columbia border to the north tip of Vancouver Island. They were later canceled.

According to the NOAA, a tsunami warning means "that a tsunami with significant widespread inundation is expected or is already occurring."